Intelligent Damping Control of Long-Distance Transmission in Large-Scale Energy Base

摘要

Series Compensated Transmission Systems and AC/DC Hybrid Transmission systems are commonly used to transport electricity from generating units in the large energy base to a long distance. These transmission systems increase the risk of sub-synchronous oscillation while improving transmission capacity at the same time. So how to improve the damping level of the sub-synchronous oscillation and ensure the safety and stability of regional power grid and generating units is one of the key issues needed to be urgently addressed in the construction of large power grids. In this paper, damping control measures used in long-distance electricity transmission are deeply researched, and methods for mitigation of sub-synchronous oscillation by improving damping are detailed introduced. First of all, the mechanism of sub-synchronous oscillation in Series Compensated Transmission Systems and AC/DC Hybrid Transmission systems has been studied in this paper. We use damping to measure the harm degree of sub-synchronous oscillation. Different solutions aimed to improve the damping were proposed and the characteristics of different methods were analyzed and compared. Second, in order to solve the sub-synchronous problem in Compensated Transmission Systems and AC/DC Hybrid Transmission systems, we proposed three damping control methods in this paper, the Supplementary Excitation Damping Control (SEDC), Generator Terminal Sub-synchronous Damping Control (GTSDC) and Sub-synchronous Damping Control method used in DC Transmission System (SSDC). In addition, we studied the principle of controller parameters design, the process of subsynchronous oscillation signal including signal extracting and filtering, the relationship and interaction of different sub-synchronous damping control methods. Above all, we put forward the field application solution which can be briefly described as follows, the combination of SEDC and GTSDC be used in AC Compensated Transmission Systems, and the combination of SEDC and SSDC be used in DC Transmission Systems to achieve the aim of improving damping of system in sub-synchronous oscillation. Finally, the function of damping control in sub-synchronous oscillation is verified by Real-time dynamic simulation based on the RTDS platform. The simulation results show that the subsynchronous damping controller can effectively improve the sub-synchronous damping level and can be used in field applications. It is an effective and economical way to solve the sub-synchronous oscillation problem in the long-distance transmission of large-scale energy base.